Pediatric Surgery: Necrotizing Enterocolitis (NEC)

Necrotizing Enterocolitis (NEC)

Basics

  • Definition: Acquired Inflammatory Disease of the Newborn Gut
  • The Most Common Newborn Surgical Emergency
  • 50% Develop Advanced Disease Requiring Surgical Intervention

Bowel Involvement

  • Can Involve Single or Multiple Segments
  • Most Common Site: Terminal Ileum
  • NEC-Totalis
    • Definition: Necrosis of ≥ 75% of Bowel
    • Occurs in 19-20% of Cases
    • Almost 42-100% Mortality

Cause

  • Cause: Multifactorial & Not Entirely Understood
    • Immature Intestinal Tract
    • Immature Immune System
    • Disruption of Normal Gut Flora, Possibly from a Period of Intestinal Hypoperfusion
  • Risk Factors:
    • Prematurity
    • Antibiotics
  • Possible Protective Factors:
    • Human Breast Milk
    • Probiotics

Presentation

  • Bloody Stool After First Feed
    • Gross Blood: 25-63%
    • Occult Blood: 22-59%
  • Abdominal Distention
  • Vomiting & Diarrhea
  • Lethargy
  • Temperature Instability
  • Recurrent Apnea & Respiratory Failure
  • Bradycardia
  • Hemodynamic Instability

NEC 1

Bell Staging

  • Bell Staging
    • Stage I: Suspected
    • Stage II: Definite
    • Stage III: Advanced
  • Modified Bell Staging
Stage Classification of NEC Systemic Signs Abdominal Signs Radiographic Signs
IA Suspected Temperature Instability, Apnea, Bradycardia, Lethargy Gastric Retention, Abdominal Distention, Emesis, Heme-Positive Stool Normal or Mild Intestinal Dilation, Mild Ileus
IB Suspected Same as Above Grossly Bloody Stool Same as Above
IIA Definitive, Mildly Ill Same as Above Same as Above, Plus Absent Bowel Sounds with/without Abdominal Tenderness Intestinal Dilation, Ileus, Pneumatosis Intestinalis
IIB Definitive, Moderately Ill Same as Above, Plus Mild Metabolic Acidosis & Thrombocytopenia Same as Above, Plus Absent Bowel Sounds, Definitive Tenderness with/without Abdominal Cellulitis or RLQ Mass Same as IIA, Plus Ascites
IIIA Advanced, Severely Ill, Intact Bowel Same as IIB, Plus Hypotension, Bradycardia, Severe Apnea, Combined Respiratory & Metabolic Acidosis, DIC & Neutropenia Same as Above, Plus Signs of Peritonitis, Marked Tenderness, and Abdominal Distention Same as IIA, Plus Ascites
IIIB Advanced, Severely Ill, Perforated Bowel Same as IIIA Same as IIIA Same as Above, Plus Pneumoperitoneum

Diagnosis

  • Definitive Diagnosis Made at Surgery
  • Clinical Diagnosis Made with History, Physical Exam & Imaging
    • Preferred Imaging: Abdominal XR
    • AXR Findings:
      • Pneumatosis Intestinalis (Hallmark of Disease)
      • Ileus Gas Pattern (Nonspecific Distention)
      • Portal Venous Gas
      • Pneumoperitoneum
    • Bedside Doppler US Use is Evolving

Treatment

  • General Management: Conservative
    • NPO & Begin TPN
    • NG Tube Decompression
    • IV Fluid Resuscitation
    • Broad-Spectrum Antibiotics
    • Serial Lateral Decubitus XR (Assess for Free Air)
  • Pneumoperitoneum, Peritonitis or Hemodynamically Unstable: Surgical Resection & Ostomy
    • May Consider Primary Anastomosis for Carefully Selected Patients with Isolated Disease
    • Pneumatosis Alone is Not an Indication for Surgery
    • Prior to Taking Ostomy Down: Barium Enema to Rule Out Developing Colonic Strictures

Post-NEC Intestinal Strictures

  • Occur in 10-40% of Patients
  • 70-80% Occur in the Colon

NEC Radiographic Findings, (A) Pneumatosis Intestinalis and Portal Venous Gas, (B) Pneumoperitoneum and Pneumatosis Intestinalis, (C) Gasless Abdomen, (D) Distended Abdomen with Periumbilical Erythema 2

References

  1. Jeican II, Ichim G, Gheban D. Intestinal ischemia in neonates and children. Clujul Med. 2016;89(3):347-51. (License: CC BY-NC-ND-4.0)
  2. Sheng Q, Lv Z, Xu W, Liu J, Wu Y, Shi J, Xi Z. Short-term surgical outcomes of preterm infants with necrotizing enterocolitis: A single-center experience. Medicine (Baltimore). 2016 Jul;95(30):e4379. (License: CC BY-4.0)